Patriot Powertrain and Chassis

Date 2007/2/13 11:41:00 | Topic: Patriot

From a Chrysler Group press release:

The all-new 2007 Jeep(R) Patriot sets a new standard for off-road capability in the compact sport- utility (SUV) segment: a fun-to-drive vehicle that delivers best-in-class Jeep 4x4 capability and class-leading fuel efficiency. The Jeep Patriot, equipped with its standard 2.4-liter World Engine, achieves 30 miles per gallon (mpg) on the highway -- fuel-economy numbers not often found on an SUV.

The 2007 Jeep Patriot's powertrain delivers world-class performance, fuel economy and refinement. Patriot features a standard 2.4-liter World Engine with dual Variable Valve Timing (VVT), which helps optimize the torque curve at all speeds. This World Engine produces more power, better fuel economy and a smoother, quieter ride than engines without dual VVT. Dual VVT is a technology typically not available on vehicles sold in the United States in the Patriot's price class. Performance objectives are targeted to match the best in the segment. The 2.4-liter engine provides 172 horsepower (128 kW) and 165 lb.-ft. (222 N*m) of torque and delivers class-leading fuel-economy of 26 mpg in the city and 30 on the highway. A 2.0-liter four-cylinder World Engine also is available on front-wheel-drive Jeep Patriot Sport models and achieves 26 miles per gallon in the city and 30 mpg on the highway.

Jeep Patriot features a standard five-speed manual transaxle and an available Continuously Variable Transaxle (CVT2). CVT2 is a second-generation CVT that Chrysler Group engineers calibrated for pleasing engine response and precise ratio control. CVT2 contributes to a fuel economy improvement of 6-8 percent compared with a traditional four-speed automatic transaxle. Patriot also is the first Jeep vehicle to offer a CVT2 with integral low-ratio (CVT2L). The CVT2L's effective first gear in low ratio is 19:1, which provides the torque necessary for crawling over moderate rocks and logs and other off- road events.

NEW TECHNOLOGY CREATES JEEP 4X4 CAPABILITY

An electronically controlled coupling (ECC), which is attached to the Patriot's rear differential, is the heart of Jeep Patriot's Freedom Drive I and Freedom Drive II Off-road Package four-wheel-drive systems. Patriot's ECC system is easier to calibrate, more flexible, more precise and lighter than viscous-coupling or gerotor systems.

The ECC transmits torque to the Patriot's rear wheels through a two-stage clutch system. An electromagnet powered by current from the electronic control module operates a low-torque clutch. A cam-and-ball mechanism amplifies the force of the low-torque clutch, applying the main clutch that transmits torque to the rear wheels. The control module calculates vehicle speed, turning radius and wheel slip and transfers torque based on these conditions. The unit seamlessly interacts with the Electronic Stability Program (ESP), Anti-lock Brakes (ABS) and Brake Traction Control systems to ensure torque is transferred as needed, providing better handling and traction characteristics.

Unlike other on-demand four-wheel-drive systems that rely on pumps or viscous fluids to transfer torque, the Jeep Patriot's four-wheel-drive system requires no front-to-rear slippage for activation. Patriot's state-of-the-art electronic four-wheel-drive system anticipates the need for added traction and responds to wheel slippage by automatically transferring power to the rear wheels. The system contributes to Patriot's excellent fuel economy by operating only when needed, minimizing power-robbing friction and inertia.

MOST CAPABLE VEHICLE IN ITS CLASS

Jeep Patriot is available in three drivetrain configurations: the standard front-wheel-drive system, which provides excellent ride and handling combined with best-in-class fuel efficiency, the Freedom Drive I 4x4 system and the Freedom Drive II Off-road Package.

Freedom Drive I is an available full-time, active four-wheel-drive system with Lock mode designed to give drivers year-round assurance for the ability to handle rough weather and low-traction conditions. This active four-wheel- drive system is recommended for daily use, including slick conditions that come with rain and light snow. Freedom Drive I features a lockable center coupling, giving drivers the ability to put the Jeep Patriot in four-wheel- drive Lock mode to handle deep snow, sand and other low-traction surfaces.

To activate the Jeep Patriot's Freedom Drive I Lock mode, the driver pulls up on the chrome T-handle. This lock mode ensures that the ECC sends the maximum amount of torque to the rear axle (up to 60 percent) for improved traction.

The Jeep Patriot's Freedom Drive II Off-road Package is available on both Sport and Limited models. This all-new Jeep technology includes the CVT2L's best-in-class 19:1 low ratio, which is ideal for crawling over obstacles. Off- road Brake Traction Control maintains forward movement during heavy articulation or on split-friction surfaces where one wheel loses traction. Hill-descent Control modulates brake hydraulic pressure without driver intervention, providing downhill assistance at a safe and controlled rate of speed. Brake lock differentials improve the Patriot's mobility by applying brake force to the driven wheel that is spinning faster than the mate on the same axle. This provides an equal amount of torque for each wheel, thereby providing torque to the wheel with the most traction. This helps when crawling over obstacles, during heavy articulation activity, or when the driver encounters split-friction surfaces or off-road driving conditions.

Trail Rated Jeep Patriot models also include a heavy-duty cooling module, a full-size spare tire, skid plates (that protect critical components like the engine, transaxle or fuel tank during off-road driving), and tow hooks designed to get even the best off-roaders out of a tight spot. Standard three- mode ESP and off-road ABS also add to the Patriot's inherent off-road capability.

Drivers can select four-wheel Lock mode on Jeep Patriots with the Freedom Drive I and the Freedom Drive II Off-road Package by pulling up once on the T- shaped off-road handle in the center console. Once the off-road handle is pulled, an amber "off-road" message in the cluster lights up to confirm the system is on.

The Patriot responds rapidly to aggressive throttle input and delivers better traction performance for off-road maneuvers than in the normal mode. At speeds less than 10 mph, the maximum amount of torque is sent to the rear axle, which effectively locks the front and rear axles together at a 50/50 torque split for optimum traction performance. At speeds less than 25 mph, the calibration for the ECC is more aggressive. At speeds above 25 mph, the coupling delivers the same amount of torque to the rear axle as in the normal mode.

When in Off-road Mode with the 4WD Lock engaged and the shifter in the "L" or low ratio position, the following conditions are engaged automatically for optimal capability and performance on Jeep Patriot Trail Rated models equipped with the Freedom Drive II Off-road Package:

* CVT2L provides an overall first gear ratio of 19:1 for crawling over large obstacles until the vehicle approaches a speed of 10 mph or more, when it ratios up to maintain speed

* Traction Control reverts to brake lock differentials to help maintain forward mobility during heavy articulation or on split-friction surfaces when one wheel loses traction

* Hill-descent Control, a first for Jeep, modulates the brake hydraulic pressure without driver intervention to provide downhill assistance at a safe and controlled rate of speed. This feature uses grade-sensing logic to determine if the vehicle is descending a hill or traveling on level ground

* A green icon showing a vehicle descending a hill appears in the cluster when the Off-road Mode is activated and CVT2L is in Low or Reverse

ACHIEVING TRAIL RATED STATUS

Jeep Patriot Trail Rated models are designed and tested to perform in a variety of off-road conditions defined by five key consumer-oriented performance categories. These include traction, ground clearance, articulation, maneuverability and water fording, as well as measurements that demonstrate the engine and transmission continue to self-lubricate, while the vehicle is traveling up a side slope or on a fore/aft grade, for consistent performance and capability. The testing for these performance criteria is performed through a combination of physical testing and virtual modeling.